Cheese-producing textile machines of the above-described type are known from various patent applications. For example, German Patent Publications DE 196 46 564 A1 and DE 196 50 932 A1 describe such textile machines, designed as automatic bobbin (cheese) winding machines. These so-called automatic cheese winders respectively have a plurality of work stations of the same type, arranged in a row next to each other. Each work station itself has a winding device with a winding drum, driven by an individual motor, as well as a work station computer.
Ring-spinning cops are rewound into cheeses of large volume in the work stations. The work stations are supplied with cops by a service unit, which can be moved along the work stations, i.e. when needed, the service unit automatically travels to the respective work station and exchanges a finished cheese for an empty cop tube which has been rewound at the work station.
Such textile machines also have a central control unit, which is connected via a machine bus with the individual respective work station computers, as well as with the control device of the service unit.
The service unit, preferably a so-called cheese changer, has numerous manipulating devices for transferring the cheeses finished on the winding device of the work stations to a cheese transport device extending over the length of the machine, as well as for the subsequent insertion of an empty cheese-winding tube into the creel.
As extensively described in German Patent Publication DE 195 33 833 A1, such cheese changers have, among other things, a yarn lifter, which is pivoted into the path of the yarn moving from the feed bobbin to the delivery bobbin at the start of the exchange process. In this operation, the yam lifter grasps the yarn, which is cross-wound from a winding drum, preferably designed as a reversing gear roller. The caught yarn is subsequently cut into an upper yarn end and a lower yarn end by a yarn cutting and clamping device arranged on the yarn lifter.
Subsequently the upper yarn end is wound on the tip of the tube of the finished cheese, for example as a top cone winding, while the bottom yarn is positioned between the tube receiver of the creel of the winding station and a fresh empty tube such that it is clamped during the subsequent locking of the empty tube. When the winding station is restarted, the tube maintained in the creel is frictionally driven by the winding drum, and in the process the lower yam end is guided by the yarn lifter in such a way that first a so-called foot or reserve winding is created on the tube foot. Thereafter, the lower yarn end, which is delivered from a ring-spinning cop, is unwound therefrom and is cross-wound in the yarn guide groove of the winding drum such that a fresh cheese is created of the "random winding" type.
Depending on the desired bobbin format, winding drums of different embodiments are used in the work stations. The winding drums used can be configured with 1.5 traverses, 2 traverses, 3 traverses, etc. However, it is disadvantageous in the known automatic cheese winders that with the yarn pick-up, which becomes necessary at the start of the exchange process, the winding drums are always driven for a fixed, predetermined length of time. This length of time is of such duration that even with winding drums with a maximum number of traverses it is still assured that the yarn is dependably fed to the yarn lifter, as a rule at least twice. Thus, the length of time, and therefore the number of revolutions which the winding drum performs during yarn pick-up, is always the same. The number of traverses of the winding drum used are completely disregarded in the yam pick-up operation.